Previous research has shown that personality hardiness is an important resource in resisting the mental and physical strain and illnesses resulting from stressful life events. Emerging as rather independent of other resistance resources, personality hardiness yields results suggesting that it is learnable. On the basis of research and clinical experience, we have theorized about how hardiness is learned in childhood, and the techniques whereby it can be taught to adults who did not develop it in childhood. The techniques are situational reconstruction, focusing and compensatory self-improvement, all of which encourage transformational coping, which in turn leads to the commitment, control and challenge dispositions framing hardiness. Once hardiness is increased, transformational coping with future stressful events is more likely. Through transformational coping, events are rendered less stressful so that subsequent strain and illness are less likely. The specific aims of this proposal are to determine, through a series of intervention experiments, whether our hardiness training program is successful in producing lasting increases in hardiness and concomitant lasting decreases in strain and severity of illness. For us, strain is a combination of mental distress (e.g., anxiety, depression, interpersonal sensitivity, demoralization) and sympathetic physiological arousal (e.g., heightened blood pressure, cortisol). If strain is intense and prolonged enough, breakdowns into definite illnesses are likely. In focusing upon severity of illness, we emphasize a composite of mental and physical disorders of varying seriousness. The series of experiments has been planned to lend precision to conclusions, to explore the generality of findings across trainers and trainees, and to begin study of cost effectiveness. The long-range research objective is to provide an effective, efficient intervention whereby persons can increase in personality hardiness and thereby decrease in the likelihood of mental and physical strain and illness. The disciplines involved in this research are personality, abnormal and health psychology, and its thrust is prevention.